Machinery such as rock breakers, impact hammers, drop hammers and the like apply significant impact forces to both the working surface being impacted and the machinery itself. The impact forces generate both a kinetic impulse and an audio shockwave, the magnitude and origin of which is dependent on numerous factors including the:                machinery size,        mass and velocity of the impacting weight,        construction of the machinery        nature of the working surface and        angle of impact.        
The effects of both the physical shock and the noise generated during impacts can have significant adverse effects on the economics of impacting operations. The machinery apparatus must be manufactured with sufficient structural strength to withstand the repetitive impacts, whilst repairs and replacements of various parts of the apparatus are required over time due to ongoing wear and tear. The additional costs of both these issues are overheads on the cost efficiencies of operating the apparatus.
Furthermore, legislation, health, safety and environmental requirements in many countries now impose restrictions on the noise levels and time periods that such impacting apparatus may be operated. Restrictions are particularly stringent in areas adjacent urban populations.
Consequently, any attenuation in the magnitude of the kinetic and/or audible effects of the impact can be realised as efficiency and cost-effectiveness improvements including;                a lighter, less reinforced, cheaper apparatus construction to produce the same impact force on the working surface;        a greater impact force on the working surface from the same impact mass, and same lifting mechanism, due to less frictional losses on both lifting and descent stroke;        noise reduction enables either the use of more powerful reciprocating mechanisms for the same volume levels, or the ability to operate closer to noise restricted areas with the same reciprocating mechanism.        
The inherent characteristics of breaking apparatus such as highly repetitive cyclical operations, high velocities of the descending weight, large shock loads that can be transferred to the apparatus, variation in properties of impact surface, angle of impact and so forth, create challenges for any material used to provide low friction interfaces between the moving surfaces of the apparatus, while having sufficient resilience to accommodate the shock loads. One method of reducing the friction in many reciprocating mechanisms is to use a lubricant coating on the surfaces that make contact. However, in many applications, particularly rock-breaking applications, wet lubricants cannot be used as the dust generated during operation will adhere to the lubricant and result in a higher-friction and abrasive interface, and dry lubricants do not always perform well on mating surfaces with low contact areas and high pressures such as rock breaker guide columns.
It would thus be advantageous to provide impact cushioning slides capable of addressing the aforesaid difficulties.
All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein; this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.
It is acknowledged that the term ‘comprise’ may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term ‘comprise’ shall have an inclusive meaning—i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term ‘comprised’ or ‘comprising’ is used in relation to one or more steps in a method or process.
It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.
Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.